<?php
/**
 * Created by PhpStorm.
 * User: zing
 * Date: 2018/5/7
 * Time: 23:54
 */


$id = 0;
$ids;
empty($ids) && printf("ids == 0\n");
empty($id) && printf("id == 0\n");
!$id && printf("id == 0\n") || printf("id != 0\n");
!!$id && printf("id == 0\n") || exit(10);